1. Field of the Invention
The invention relates to a cooling channel cover for a one-piece piston of an internal combustion engine, the piston having a closed cooling channel that runs around inside the piston crown, at the level of the piston ring band, and a ring-shaped recess provided between the piston ring band and the piston shaft. The piston shaft is connected with the piston hubs suspended on the piston crown.
2. The Prior Art
A multi-part cooled piston having a cooling channel arranged in the edge region of the piston head is described in German Publication DE 40 39 751 A1. This channel is covered with a sheet-metal ring essentially structured like a cup spring. This sheet-metal ring is structured in one piece and can be easily assembled with the piston only because the piston is structured in two parts. It is necessary to assemble the sheet-metal ring with the upper piston part first, before the upper piston part is connected with the lower piston part.
Furthermore, pistons are known from German Publication No. DD 252 638 A1 and German Publication No. DE 41 34 530 A1, in which a wall part that covers the cooling channel that is open to the bottom, and runs around the circumference in ring shape, is structured as an open sheet-metal ring, which rests in a groove against the inside circumference of the piston ring zone, and against the outside circumference of the combustion chamber wall, respectively, taking advantage of its plastic deformation according to the Seeger ring principle, i.e. biased in the radial direction.
Furthermore, a multi-part piston having a cooling channel is known from German Patent No. DE 42 08 037 C2, in which the cooling channel, which is open to the bottom, is covered by means of a biased cup spring, which is divided into at least two parts on its circumference, and rests freely on supports against axially opposite sides, radially on the inside and the outside.
Finally, one-piece cooling channel pistons having a cooling channel arranged in the edge region of the piston head are known from European Patents Nos. EP 0 561 871 B1 and EP 0 799 373 B1, which channel is also closed off with cover rings structured like cup springs, or cover rings structured like cup springs and provided with a collar.
In this connection, a disadvantage of the aforementioned embodiments is that the cover ring or cup spring must be structured in two parts, in order to be able to be assembled. Furthermore, during assembly each of the two semi-circular ring halves must be individually introduced into corresponding bearings on the piston crown, in the biased state.